Ford 6640 Dash display problems

[JW IN VA]

My '94 6640 Sl has developed two problems in the gauge cluster this week.
First,the fuel gauge stopped registering.I checked the wires since I had blown out the radiator area but they were hooked solidly.
Wasn't terribly concerned,for now,since I could watch the hours and guesstimate when it was time to fill up.That was until today when I noticed the hour meter had stopped counting at 6189.8.
I've had the hour meter stop before when a voltage drop occurred because of a faulty battery temperature sensor which was replaced with an upgraded fix last year.At that time,neither the PTO switch nor the tach would work,either.
I have both the PTO and tach needle working right now.

Any suggestions about what to test or check would be appreciated since I'd rather not buy a new outfit if I don't need one.

My display is all analogue.Just conventional fuel and temp gauges plus a row of warning lights.

 

[jltrent]

If not already check the ground wire at the battery. Attachment to the battery clean good and also the other end to the frame. Since you have multiple things not working it sounds like a power issue. Also rats can work on wires, but usually not this time of year. Squirrels would be worse this time of year. Just throwing things out there, but it could be the voltage regulator as had that happen on a Ford 3600 and things went wacky. Also make sure the dash cluster is grounding.

 

[ERNIBIGB]

The circuit boards in those clusters are bad to give problems. My 7740 hour meter has not worked for the 10 years I have owned it. I sometimes slap the dash to get tach and fuel to work . Someone who works on circuit boards could possibly repair it